Power Industry Boiler Water Level Measurement Techniques

The March 2017 Inst Measurement and Control Technical Seminar evening will be hosted by Doosan Babcock in Manor Royal, Crawley, on Tuesday 21st March 2017.

This will be a tri-company, collaborative event, presented by Doosan Babcock, and also featuring contributions from Vega and TC-Fluid Control. It is aimed at providing attendees with a useful insight into industrial measurement application challenges in order to further their professional development knowledge.

Drum Level Control

The first presentation by Doosan Babcock will discuss Drum level measurement using DP Measurement and Hydrastep Measurement techniques.

Power station Steam Drum Level measurement is required for drum level control, Burner Management System (BMS) protection and Code compliance. Drum level is both a critical and difficult measurement to make. At steady state conditions, considerable turbulence in the drum can cause the level to fluctuate. A changing rate of water inflow and steam outflow adds to the potential for measurement error. The DP Measurement technique uses the difference in pressure between a head of water in an external reference column and the level in the drum. The density of water and steam vary appreciably with pressure, so the differential pressure obtained at any given level will vary as boiler pressure changes.

The Hydrastep technique detects the conductivity variation between the steam and the water. The electrode principle is an efficient system for measuring drum water levels.

Microwave Technology

Vega will explain how microwave technology can tackle a wide variety of applications associated with steam boilers. Non-contact or guided wave techniques have the ability to measure reliably, even with fluctuating temperatures up to 450C combined with pressures of up to 400 bar. Measurement is virtually unaffected by pressure and temperature changes. Top mounting makes installation and maintenance easy. In many cases microwave transmitters provide an alternative to legacy equipment for both solids and liquids. SIL qualification and boiler approval now enables microwave technology to  be used directly on steam boilers, with special modifications to compensate for saturated steam effects.

Visual/Glass and Boiler Steam Glass level gauges

untitledVisual/Glass and Boiler Steam Glass level gauges are a requirement on steam boilers for visual verification of the level control system, and will be discussed by TC-Fluid Control. Magnetic level gauges have many applications on and around the boiler, providing visual level indication whilst minimising potential leak paths, and can be used as an alternative to one of the glass level gauges on the boiler drum. Simple, robust technology provides a highly visible indication of process level at pressures of up to 400 bar and temperatures up to 450C.

Postscript: Wessex IMC Section meeting

Vega Controls will also give a talk to the IMC Wessex Section meeting on 15th March about the technology behind their 80GHz radar liquid level measurement systems. The talk will include live demonstrations, and takes place at the Forest Lodge Hotel, at Lyndhurst. A video is available that shows their new sensor.

 

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